1. Field of the Invention
The present invention concerns a method of monitoring a sensor for sensing the flow speed of a medium. The invention further concerns an apparatus for carrying out that method.
2. Description of the Related Art
It is already known from JP 11072502 to test the anemometer which is operating defectively in a process or to establish defective operation thereof. In that situation, the signal of the anemometer is evaluated by means of a computer and, with varying wind conditions, the evaluated data are compared and an error signal can be deduced therefrom.
JP 57-198870 discloses a test device for anemometers, in which anemometers are tested under working conditions. U.S. Pat. No. 4,331,881 discloses how an anemometer can be used in a wind power installation, the signal from the anemometer being used to control the wind power installation.
Sensors for monitoring flow speeds of media which are capable of flow have long been known. Quantitative flow speed meters are used in many variations, in dealing with liquids. Anemometers for example are used in the most widely varying structural configurations in relation to gaseous media which also include air.
Those sensors are frequently exposed in situ to environmental conditions which can adversely effect reliable operability thereof. For example, anemometers arranged on wind power installations, depending on the weather, can certainly be subjected to icing. It will be easily appreciated that such an iced-up anemometer can scarcely still ascertain and deliver a correct value for the flow speed of the air. Redundancy does not afford a satisfactory solution here, as the redundantly provided anemometer is naturally also subjected to the icing effect.